Menghong Gr
Type Locality and Naming
The type section lies at the back of Menghong Village, 20 km from southwestern Tengchong City, Yunnan. It was named by Fang Zhongjing in 1962.
Lithology and Thickness
Siltstone and Glacial-marine Pebbly Siltstone. Consisting of three parts. Lower part: in the southern part of the Tengchong massif, it is formed by gray or light purple-red thin- to medium-bedded siltstone, clayey siltstone and mudstone, ~600 m thick; in the northern part, formed by gray-white medium-bedded to massive quartz sandstone, ~700 m thick. Middle part (Glacial-marine) is dominated by gray pebbly siltstone and pebbly mudstone, intercalated with thin-bedded siltstone, mudstone and sandstone, in which the pebbles are composed of vein quartz, quartzite, quartz sandstone or slate and shale fragments, 500−900 m thick. Upper part consists of gray, blue-gray or black mudstone and shale with limestone lenses, 100−150 m thick. Some of the horizons are slightly metamorphosed.
Relationships and Distribution
Lower contact
Unknown: the contact relationship with the underlying stratum is unclear
Upper contact
Conformable contact with the overlying Permian Guanyinshan Fm (not in Permian Lexicon) -- Kongshuhe Fm is indicated in Permian Lexicon as the overlying formation.
Regional extent
GeoJSON
Fossils
Middle part yields brachiopods, bivalves and bryozoans. Upper part yields fusulinids Triticites parvulus, T. chinensis, Schwagerina pararegaria and Hemifusulina pseudosimplex; foraminifers Cribrogenerina inepta and Nodosaria longissima as well as bryozoans and brachiopods.
Age
Depositional setting
The pebbly clastic rock in the middle part may be a glacial-marine deposit (Jin, 1994), while the other horizons are deposits of the offshore and neritic facies.
Additional Information